Embodiments of the invention relate generally to integrated circuit packages and, more particularly, to a buried die build-up that uses low resistance metal interconnects directly to the chip bond pad or electrical component connection pad, allowing higher device speeds, lower power consumption, and smaller size. Buried die modules can be manufactured having one or more dies or electronic components in. The plurality of dies or electronic components are electrically connected to an input/output system by way of metal interconnects routed through a plurality of laminate flex layers.
As integrated circuits become increasingly smaller and yield better operating performance, packaging technology for integrated circuit (IC) packaging has correspondingly evolved from leaded packaging, to laminated-based ball grid array (BGA) packaging, to chip scale packaging (CSP), then flipchip packages, and now buried die/embedded chip build-up packaging. Advancements in IC chip packaging technology are driven by ever-increasing needs for achieving better performance, greater miniaturization, and higher reliability. New packaging technology has to further provide for the possibilities of batch production for the purpose of large-scale manufacturing thereby allowing economy of scale.
Advancements in IC chip packaging requirements pose challenges to the existing buried die build-up process. That is, it is desired in many current buried die modules to have an increased number of re-distribution layers, with eight or more re-distribution layers being common. The standard buried die build-up process, in which the one or more dies are initially placed on the IC substrate and the re-distribution layers are subsequently applied in a layer-by-layer fashion, can lead to warpage in the rerouting and interconnection system, requiring the use of a molded epoxy stress balance layer or metal stiffener.
Another challenge to the existing buried die build-up process is the time of the manufacturing/build-up cycle. A major contributor to the build-up time is the multiple curing steps that are performed for curing the plurality of adhesive layers included in the buried die module, such as multiple baking steps.
Accordingly there is a need for a method for buried die fabrication that provides a shorter manufacturing cycle time and allows for the application of multiple laminate layers while minimizing warpage of the module without the use of a stiffener.